Question

我试图找出为什么我的微调器不会保持整数。当我运行程序时，问号出现在微调器而不是1,2,3,4等等一直到100.我是Swift的新手，这是我第一次使用微调器/ Picker 。我的程序应该计算每加仑的里程数，但如果我不能让微调器工作，那就不会发生，哈哈。

以下是设置变量和微调器的代码：

class SecondViewController:
UIViewController,UIPickerViewDataSource,UIPickerViewDelegate
{
    var BlopSoundURL =  NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("Blop", ofType: "mp3")!)

    var soundAudioPlayer = AVAudioPlayer()

    var miles = 0.0
    var gallonsUsed = 0.0
    var mpg = 0.0

    // Variables for slider
    var minMiles = 1
    var maxMiles = 1000


    @IBOutlet weak var milesDrivenLabel: UILabel!

    @IBAction func milesDrivenSlider(sender: UISlider)
    {

    }

    @IBOutlet weak var gallonsUsedPicker: UIPickerView!
    let pickerData = [1,2,3,4,5,6,7,8,9,10,11,
                12,13,14,15,16,17,18,19,20,21,
                22,23,24,25,26,27,28,29,30,31,
                32,33,34,35,36,37,38,39,40,41,
                42,43,44,45,46,47,48,49,50,51,
                52,53,54,55,56,57,58,59,60,61,
                62,63,64,65,66,67,68,69,70,71,
                72,73,74,75,76,77,78,79,80,81,
                82,83,84,85,86,87,88,89,90,91,
                92,93,94,95,96,97,98,99,100]

还没有提交按钮的代码，但这里是微调器和程序的其余代码：

@IBAction func submitButton(sender: UIButton)
{
    soundAudioPlayer.play()
    let row = gallonsUsedPicker.selectedRowInComponent(0)

}



func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
{
    return 1
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
{
    return pickerData.count
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> Int!
{
    return pickerData[row]
}


override func viewDidLoad()
{
    super.viewDidLoad()

    gallonsUsedPicker.dataSource = self
    gallonsUsedPicker.delegate = self

    soundAudioPlayer = AVAudioPlayer(contentsOfURL: BlopSoundURL, error: nil)
    // Do any additional setup after loading the view, typically from a nib.
}   // End of viewDidLoad

override func didReceiveMemoryWarning()
{
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}   // End of didReceiveMemoryWarning


}   // End of SecondViewController

我真的不确定函数中的代码是什么，因为这本书没有很好地解释它。然后，我将不得不弄清楚如何从微调器中取出数字并将其存储在变量中，以便我可以进行mpg计算。我知道如何使用滑块，但不是旋转器。它基本上是一回事吗？我觉得这会变得有趣。谢谢，非常感谢您的帮助。

Answer 1

首先通过Swift约定，你应该用小写字母命名你的变量，并使用URLForResource（withExtension :)方法找出本地资源的URL：

let blopSoundURL = NSBundle.mainBundle().URLForResource("Blop", withExtension: "mp3")!

其次，选择器值应为String：

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 1
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
    return "\(row+1)"
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return 100
}

你可以使用

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    // do whatever with row+1  here
}

// or 

@IBAction func submitButton(sender: UIButton) {
    soundAudioPlayer.play()
    let rowValue = gallonsUsedPicker.selectedRowInComponent(0) + 1

}

Swift微调器/拾取器未保持或显示整数

1 个答案: